This invention relates to machine tools and more specifically to a flexible tooling apparatus for providing a support deck for use with machine tools or assembly tools for processing materials.
When machining material with machine tools, assembling material for fastening, or performing other processing, such as heat curing, it is necessary to provide a support system for the material being machined or operated upon. In the past, such supports have comprised a tooling support which substantially conforms to the three-dimensional shape of the part or item being processed. The cost to design, fabricate and store such tooling supports can become prohibitive. A separate tooling support is required for each uniquely shaped item being processed. Often the setup time and effort to prepare and position the tooling die becomes greater than the time involved in actual machining or processing of the part.
To resolve some of the drawbacks of the fixed tooling die situation, variable tooling supports have been developed, for example, as described in U.S. Pat. No. 5,372,357, wherein a plurality of spaced supports are provided in fixed relation to one another and the supports are adjusted heightwise to support the work piece at certain points. The work piece is then either clamped to the supports or the supports provide some sort of clamping through the use of vacuum at the suction cups, for example.
Heretofore, these systems have been quite expensive and complex with a large number of interactions required to provide the appropriate control and power to cause the raising and lowering, as well as the application of vacuum to each of multiple support members. Variable systems which allow movement of the support stanchions in a horizontal plane, as well as the vertical extension thereof, provide even further difficulties given that control wires, power wires and hydraulic or pneumatic or vacuum supply lines are required to also be movable. Maintenance costs related to such systems can be quite high. Over the useful life of such an apparatus, the potential for failure of electrical connections, for example, becomes greater with each successive movement. Further, the cost of such systems is out of the reach of many businesses and such a system may be overly complex for small business applications.
The design of flexible tooling systems is further complicated because of the high temperatures at which many modern manufacturing processes are performed. Such processes include heat treatments, coating applications, and formation of parts from composite materials, which formation can take place at around temperatures of around 400.degree. F. (204.degree. C.). At high temperatures, adequate work piece support can be critical because work pieces tend to deform more readily under their own weight.
Some known clamp mechanisms that fix the extensible supports at the desired extension can loosen at high temperatures, due to thermal expansion of the parts in the clamping assembly. Other clamps tend to bind at high temperatures due to the uneven expansion of the parts in the clamping assembly, thereby preventing releasing of the clamp. Moreover, at high temperatures, the hydraulic systems used to clamp the extendible supports tend to have more problems, such as leaks caused by thermal expansion of fittings and reduced useable lifetime of hydraulic fluids, not to mention the safety issues that arise with flammable fluids in an elevated temperature environment.